Craig, Robin Kundis
Thomson/West, 2008
Buku Teks
Gray, Oscar S.
The Bureau of National Affairs, 1973
Buku Teks
Rose, Jerome G.
The State University of New Jersey, 1974
Buku Teks
Kauper, Paul G., author
Little, Brown, 1971
Buku Teks
Barrett, Edward L., author
Foundation Press, 1977
Buku Teks